Every year over 400,000 Americans die from some type of lung disease and that number is larger worldwide. Moreover, death rates due to lung diseases are currently increasing. According to the American Lung Association, chronic obstructive pulmonary disease (COPD) is expected to become the third leading cause of death by 2020.
A lung disease is any disease or disorder where lung function is impaired. Lung diseases can be caused by long-term and/or immediate exposure to, among other things, smoking, secondhand smoke, air pollution, occupational hazards such as asbestos and silica dust, carcinogens that trigger tumor growth, infectious agents, and over reactive immune defenses. Over a period of time, lung tissues including the airway and blood vessels become damaged such that there is not enough healthy tissue to support adequate gaseous exchange to supply sufficient oxygen for all the cells in the body for basic function. In essence, these people “suffocate” slowly to death. Therefore, lung disease can be a life-threatening illness or condition.
There are many types of lung diseases including: (A) Obstructive lung diseases such as asthma and COPD which includes chronic bronchitis and emphysema. These all affect a person's airways and limit or block the flow of air in or out of the lungs; (B) Infectious illnesses such as pneumonia, influenza, respiratory syncytial virus (RSV) and tuberculosis (TB). Bacteria or viruses cause these diseases that can also affect the membrane (or pleura) that surround the lungs; (C) Lung cancer which is a disease characterized by uncontrolled growth and spread of abnormal cells; (D) Respiratory failure, pulmonary edema, pulmonary embolism and pulmonary hypertension. These conditions are caused by problems with the normal gas exchange and blood flow in the lungs; and (E) Pulmonary fibrosis and sarcoidosis. These are diseases characterized by stiffening and scarring of the lungs and occupational diseases, such as mesothelioma and asbestosis, caused by expo-sure to hazardous substances.
Currently, all treatments for lung diseases are mainly palliative, where the emphasis is on maintaining quality of life through symptom management. Lung transplantation is the therapeutic measure of last resort for patients with end-stage lung disease who have exhausted all other available treatments without improvement. As of 2005, the most common reasons for lung transplantation in the United States were: 27% chronic obstructive pulmonary disease (COPD), including emphysema; 16% idiopathic pulmonary fibrosis; 14% cystic fibrosis; 12% idiopathic (formerly known as “primary”) pulmonary hypertension; 5% alpha 1-antitrypsin deficiency; 2% replacing previously transplanted lungs that have since failed; and 24% other causes, including bronchiectasis and sarcoidosis.
Lung transplantation or pulmonary transplantation is a surgical procedure in which a patient's diseased lungs are partially or totally replaced by lungs which come from a donor. While lung transplants carry certain associated risks, they can also extend life expectancy and enhance the quality of life for end-stage pulmonary patients. Often, a combined heart and lung transplantation is done because both organs are intricately connected physically and functionally, and a dual transplant greatly increases the success of the transplant. However, the availability of a dual or even a single organ for transplant is very rare because certain criteria for potential donors must be fulfilled, e.g. health of donor, size match, the donated lung or lungs must be large enough to adequately oxygenate the patient, but small enough to fit within the recipient's chest cavity, age, and blood type. As a result, patients often die while on the waiting list.
Even for those lucky enough to receive a transplant, the average survival of a lung transplant patient is about 5 to 10 years which is relatively low compared to other type of organ transplantation; for lung transplant 53.4% and 28.4% respectively, and for heart-lung transplant 46.5% and 28.3% respectively (data taken from 2008 OPTN/SRTR Annual Report, US Scientific Registry of Transplant Recipients).
Sometimes, a lung transplant is not an option. Not all patients with lung disease make good candidates for lung transplant. Sometimes, despite the severity of a patient's respiratory condition, certain pre-existing conditions may make a person a poor candidate for lung transplantation. These conditions include: concurrent chronic illness (e.g. congestive heart failure, kidney disease, liver disease); current infections, including HIV and hepatitis, current or recent cancer; current use of alcohol, tobacco, or illegal drugs; age; within an acceptable weight range (marked undernourishment or obesity are both associated with increased mortality); psychiatric conditions; history of noncompliance with medical instructions; and previous multiple failed lung transplantation.
In addition for those patients having under gone a lung transplant, there may be other complications associated with the transplant which include organ rejection, post-transplant lymphoproliferative disorder, a form of lymphoma due to the immune suppressants, and gastrointestinal inflammation and ulceration of the stomach and esophagus.
Other solutions that supplement the palliative care that keep these patients alive are desirable, for example, for those on the waiting list, and especially those patients that do not qualify for lung transplant. Solutions that keep the patients off the lung transplant waiting list are also desired.